Apparatus for the cutting of skin grafts



March 25, 1941. E, J POTH APPARATUS FOR THE CUTTING OF sxm GRAFTS Filed May 10, 1959 2 Sheets-Sheet 1 INVENTOR fagaro/h BY? ATTORNEY March .25, 1941. E P TH 2,236,067

APPARATUS FOR THE CUTTING OF SKIN GRAFTS Filed May 10, 1939 'FIIS S 2 Sheets-Sheet 2 434 F'IE E FIE E 1/ J2 Z9 75 J9 INVENTOR Wm M ATTORNEY Patented Mar. 25, 1941 r i v UNlTED STATES PATENT OFFICE APPARATUS FOR THE CUTTIN F SKIN GRAFTS Edgar J. Poth, San Francisco; Calif., assignor to The Board of Trustees of the Leland Stanford Junior University, a body corporate of California Application May 10, 1939, Serial No. 272,774

3 Claims. (01. Bil-20) This invention relates generally to instruceiving the needles M. A removable clamping ments for the cutting of skin grafts, particularly plate I6 is carried by bar l2, and the removal grafts from the human skin. of this plate enables the replacement or renewal It is an object of the invention to provide an of needles. The ends of bar it are attached to improved instrument of the above character, a yoke H, which in turn is attached to the chain 5 which will be more practical than instruments it. The needles M are suitably spaced apart so heretofore available for this purpose, and which that their points Hi can properly enter and grip can be used with good results by the average the skin. Each yoke I1 is preferably bent at an technician. angle as shown. in Fig. 2, in order to tend to A further object of the invention is to provide urge the needle points into the skin as tension is 10 a retractor which will facilitate the cutting of applied. v skin grafts from difierent parts of the body, The traction bar H is substantially U-shaped without interfering with the working space above as shown in Fig. 1, and its end portions 2| are the area from which the graft is taken. provided with simple means of attachment to Another object of the invention is to provide the chains it. Thus in. this instance studs or 5 an, improved form of knife for cutting skin pins 22 are carried by the traction bar portions grafts which can be readily adjusted for cuts of 2|, and these pins may be engaged by any of the diiferent thicknesses, which makes use of a novel links of the chains It, substantially as shown in blade assembly capable of renewal at a minimum Fig. 2. This form of attachment, together with of cost without grinding, and which facilitates the use of a chain or like flexible connection to cutting grafts of large areas with a high degree the yokes l'l, forms what may be termed an adof uniformity as tothickness. iustable swivel connection.

Further objects of the invention will appear Assuming that the two retractor elements are from the following description in which the preapplied to the skin of a donor substantially as 23 ferred embodiment has been set forth in detail in shown in Fig. 1, and the chains l8 attached to Q5 conjunction with the accompanying drawings. the traction bar so that a proper amount of Referring to the drawings: tension is applied to the area of skin between the Fig. l is a plan view showing the parts of retractor elements, the working space above the my retractor, and its method of application to stretched area of the skin is unobstructed. This the skin. is true irrespective of what portion of the body 30 Fig. 2 is an enlarged detail showing the manthe device is applied to, since the traction bar ll nor in which each retractor element is conmay always be swung to an out-of-the-way posistructed, and is attached to the traction bar. tion.

Fig. 3 is an enlarged detail, partly in cross- Although any knife may be utilized with the section, showing the manner in which the needle retractor apparatus described above, I prefer to 35 points are mounted in the retractor element. make use of the adjustable form of knife illus- Fig. i is a cross-sectional detail taken along the trated inFigs. 5 to 9 inclusive. This knifecomline 4-4! of Fig, 3, prises a frame 26, formed by the end blocks 27 Fig 5 is a tt plan i showing my dand a blade assembly 28. The blade assembly 4-0 justable cutting knife. includes a plurality of aligned safety razor blades '40 Fig. 6 is a top plan viewof the same knife 29 retained by the rigid mounting 3i. Overlying shown in Fig. 5. the mounting 3| there is a bowed spring strip 32, Fig. '7 is a cross-sectional detail taken along the lower edge of which engages the safety razor the line 'l-l of Fig. 6. blades and retains them in proper alignment Fig. 8 is a cross-sectional detail taken along the upon the mounting 3|. Strip 32 is supplemented 45 line 8-8 of Fig. 6. by the inner element 33, for the same purpose. Fig. 9 is an enlarged cross-sectional detail The inner edges of the safety razor blades 29 taken along the line 9-9 of Fig. 6. engage an abutment shoulder 34, whereby the 0 Referring first to the retractor apparatus il-v cutting edges of the blades are brought into lustrated in Figs. 1 to 4 inclusive, it makes use proper alignment. The shoulder 34 prefe b of a pair of retractor elements I I], in conjunction has a slight curvature in the direction of its with the traction bar II. While the details of length, to insure a continuous cutting edge. The construction may vary, each retractor element end portions of the mounting 3| are adjustably has been illustrated as comprising a flat bar I2, and removably attached to the frame as by which is provided with spaced notches 13 for remeans of bolts 35. :55

Attached to the blade mounting 3|, there is a stationary depth guide bar 36, and at the forward side of the frame there is an adjustable depth guide 31. The latter is in the form of a fiat rigid bar, with its ends slidably carried within grooves 38,, formed in the blocks 21. In order to manually adjust the position of guide 31, I have shown a rod 39 extending through the frame, and with oppositely threaded portions 4|. These threaded portions carry threaded blocks or nuts 42, whereby when rod 39 is turned by manipulating the end knobs 43, the nuts 42 traverse in opposite directions. Each nut 42 has a pivotal connection 44 with a link 46 and the other end of each link has a pivotal connection 41 with the depth guide 31. Thus the traversing of nut 42 by rotating rod 39, causes the depth guide 31 to be raised or lowered with respect to the frame. The nuts 42 are provided with tabs 48, for sliding engagement with the longitudinal stay rod 49.

As can be understood by reference to Fig. 8, when the knife described above is in use, the lower edges of the depth guides 36 and 31 engage the surface of the tensioned skin. Now by adjusting the forward depth guide 31, the depth of the out can be accurately regulated.

For the convenience of an operator a handle 51 is attached to one end of the frame, and this handle can be removed and attached to the other end of the frame as indicated in dotted lines, for either right or left handed use.

The knife described above requires little experience for its proper use. It is particularly applicable in connection with retracting apparatus such as shown in Figs. 1 to 4 inclusive, because the knife works best with an evenly tensioned area of skin. By the use of my knife relatively large grafts can be taken with a high degree of uniformity as to thickness. The safety razor blades form a highly efiicient cutting edge, which can be readily renewed by the simple expedient of applying new razor blades. It should be understood however, that a single blade of suitable length can be employed in place of the several safety razor blades.

I claim:

1. In apparatus for the cutting of skin grafts, a pair of retractor elements each provided with a row of needle points for engagement with the skin of a donor, a substantially U-shaped traction bar, and means forming single points of swivel connection between each of said retractor elements and the side branches of said traction bar, said points of swivel connection being adjustable to accommodate for varying distances between said retractor elements.

2. In apparatus for the cutting ofskin grafts, a pair of retractor elements each provided with a row of needle points for engagement with the skin of a donor, a traction bar connected to said elements, said traction bar being adapted for disposition at one side of the skin area between said retractor elements, whereby to leave said area entirely free for both visual and manual access, and flexible connecting means between each of said retractor elements and said traction bar whereby tension can be applied to said elements to apply tension to said skin area, said connecting means providing for varying lengths between each of said elements and said bar whereby to selectively apply the desired amount of tension to said skin area.

3. In apparatus for the cutting of skin grafts, a pair of retractor elements each provided with a row of needle points for engagement with the skin of a donor, a substantially U-shaped traction bar, and chains having single points of swivel connection between each of said retractor elements and the side branches of said traction bar, the connection of said chains to said retractor elements and the associated side branches providing for adjustment of the respective lengths of the chains to accommodate for varying distances between said retractor elements as well as to provide for application of the desired tension to the skin area between said retractor elements by adjustment of said retractor elements.

EDGAR J. POTH. 

